It’s hard to think of a genre more committed to sustained creative careers than bluegrass. Case in point: the 41-years-and-counting path of Mountain Home Music Company stalwarts, Lonesome River Band. Though the last remaining original member departed before the turn of the century, the group — a quintet for more than 20 years now — hasn’t so much reinvented itself as refined a profoundly influential signature sound that has a seemingly endless appeal to successive generations of fans and musicians alike.